Instrument for use in learning telegraphy



J. E. SMITH AND C. W. BURGER.

' INSTRUMENT FOR USE lN LEARNING TELEGRAPHY.

APPLICATION FILED MAY 21. 1920.

1,394,768. Patented 00 25, 1921.

2 SHEETS-SHEET I.

1. E. SMITH AND cfw. BURGER.

INSTRUMENT FOR USE IN LEARNING TELEGRAPHY.

I APPLICATlON FIILED MAYZI, I920. 1,394,768. Patented 001;. 25, 1921..

2 SHEETS-SHEET 2.

I INVENTORJS 75 M ATTORNEY.

lowered by a cam to bring the carries the drum UNITED STATES PAT EMT QFFEQE.

JAMES EJSMITH AND CLARENCE W. BURGER, OF WASHINGTON DISTRICT OF I COLUMBIA.

INSTRUMENT FOR USE IN Application filed May 21,

To all whom it may concern:

Be it known that we, JAMES E. SMITH and CLARENCE W. BURGER, citizens of the United States, residing at Washington, in the District of Columbia, have invented new and useful Improvements in Instruments for Use in Learning Telegraphy, of which the following is a specification.

This invention relates to instruments for the use of students in learning telegraphy, and consists in certain improvements which we have made in instruments of this kind, whereby a much more satisfactory rendition of the signals and more efiicient operation are attained This machine is constructed and arranged so that it transmits to a circuit, containing a sounder or, preferably, a telephone receiver,a succession of dot-and-dash signals, which succession of signals can be varied from time to time, whereby the student learns to interpret telegraphic messages, either by wire or wireless, according to the orse, or any other system.

rior machines of this kind have. comprised one, or a plurality of disks formed with projections on the periphery, engaged by a spring arm, arranged to close a circuit whenever it encounters one of said projections. In the instrument comprising'a plu rality of disks, the spring arm was mounted in a vertically adjustable carrier raised and arm in the planes of the different disks.

ur machine attains the same result in a radically difi'erent way, as will be apparent from the following detailed description, taken in connection -With the accompanying two sheets of drawings, in which, Figure l is a plan view of the instrument; Fig. 2 a front elevation; Fig. 3 an end elevation; Fig. 4 a section on line H of Fig. 1; Fig. 5 a detail of one part of the mechanism; Fig. 6 a section on line 6-6 of Fig. 5. and Fig.

a diagram of the circuit through which the signals are received. 1

The machine comprises a box or casing 1, containing a spring motor 2, wound by a handle 3 and controlled by a -governor 4. The motor drives, through the gearing 5 and 6, a vertical shaft 7, which projects 'upwardly through the cover of the box and 8, comprising the hub 9, spokes 10, and rim 11, of metal, such as brass. The boss or ear where each spoke,

LEARNING TELEGRAPHY.

, Patented Oct. 25, 1921. 1920. Serial No. 383,189.

Letters Patent.

five in number as shown, meets the rim, is provided with a vertical hole for the reception of a pin 12, function of which will be hereinafter described. Fitted onto the periphery of the drum is a sleeve 13 of insulating material, such as bakelite, through which are drilled a plurality of horizontal rows of holes 14 of two different diameters, in which holes are secured tions of wire, the inner ends of which are in contact with the rim of the drum and the outer ends lie flush with the surface of the insulating sleeve.

The governor 4 is controlled by the thumb screw 16 through lever 17, whereby the speed of the motor, and consequently of the drum, can be varied as desired. 3

On the cover of the box or case ismounted short brass pins, or sec- 1 a U-shaped bracket 18, in the ends of the the horizontal rows of contacts on the drum and are arranged so that each arm is in the plane of one of said rows, as will be obvious. On the lower end of theshaft .or cam 19 is mounted a star wheel 21, with which are adapted to I engage) pins 12, hereinbefore mentioned, so that, as the drum rotates, the star wheel, and withit the cam, will be given a partial turn whenever one of the pins engages the wheel. The cam shaft 19 is provided with a flat place or groove 23 for each of the spring 'arms. said grooves being spaced around the cam so that only one of them will receive an arm atone time. In the instrument illustrated, there are ten spring contact arms. ten and ten rows of contacts on the drum. At any given moment, nine of the arms will be held away from the surface of the drum by the cam,'while one arm will be in the corre sponding groove in the cam and, consequently, in-engagement with the periphery ofthe drum. The pins are adapted to be held raised so as not to come into contact with the star wheel, each pin having. for

grooves in the cam,

11 0 a rece s. in the s e at the p e ga transformer *a -circuit-closing switch 30, an'd,if desired, "a telegraph key 81. stitute "no part of shown merely toillustrate the mode of use to give the cama partial turn,

boss or car when the pin is in operative position, but which rests on the top of said boss or ear when it is not desired to have the pin engage the star wheel. It will be seen that this construction provides for a great variation in the sequence of signals or contacts made, since, if only one pin is lowered, the cam will only be turned at the completion of each complete rotation of the drum, while, if two, three, four or five pins are in operative lowered position, the star wheel and cam will be turned a corresponding number of times ineach rotation of the drum.

The bracket 18 is insulated, as shown at 32 from the box or case, and carries one of the terminals 25 of the instrument, the other connecting the box or case in the circuit and, through it, the drum and the contact pins carried on the periphery of the same. Thus the circuit is closed whenever the spring arm, which is in engagement with the drum, encounters one of the contact pins. As stated, the diameter of these pins is varied so that some of them keep the circuit closed longer than the others, thereby emitting dotand dash signals.

As indicated in Fig. 7, the circuit connected to the instrument at the terminals 25, comprises a telephone receiver ear piece 26, 27,,a buzzer(28, a battery 29,

These, of course, concur inventlon, and are of our instrument, which will be clearly understood, it is thought, from the above description.

The'instrument' provides "for any desired "rapidity'of the signals aswell as for a wide 'range'of variation in the sequence of the signals, that is, of the=messages emitted, so

that'it is perfectly adapted for the use of students just beginning to learn telegraphy as well as those further advanced. The instrument operates with great smoothness and'ste'adiness, since there are no projections and recesses'to be engaged by the contact arms-and practically no power is required so that there is no danger of the instrument sticking or being slowed down when the contact engage- 'ment is s'hiftedirom-one'row of contact pins I on the drum to another.

Obviously, the invention is not limited to the exact form of construction shown and described, and'detail changes may be made 'without departing from the principle of the invention, as ex pressed in the claims.

'Having thus described our invention, what we 'claimis: F f

, ILA learners telegraph instrument, comprising a rotatable drum-carrying a plu- '-'rality' of circlesof long andshort contacts,

f'contact arms arranged bearf pn saideq contactsggnansengaging all of said arms and shaped to allow only one of them to occupy operative position at any one time, and connectionsbetween'said-drum and means whereby the latter is moved from time to time to bring another arm into operative position;

2. A learners telegraph instrument, comprising a rotatable drum carrying a plurality of circles of long and short contacts, a spring contact arm for each circle, a cam arranged to hold a predetermined number oi said arms out of contact at any time, means to rotate said drum, and means carried by said drum to turn said cam intermittently. 7 l

3. A learners telegraph instrument, comprising a rotatable drum carrying a plurality of circles of long and short contacts, an equal number of contact arms arranged to bear on said contacts, a grooved shaft on which said arms bear and which holds all of them but a certain number out of contact position, a star wheel on said shaft, and pins carried by said drum in position to engage, said wheel.

4:. In an instrument of the kind described, the combination of a rotatable'drum provided on its periphery with a plurality of parallel rows of insulated contacts of two different sizes, a plurality of spring contact there being one arm for each row, a cam engaging all of saidarms and constructed so that only one arm at a time can engage 100 the drum, means to actuate said cam from time to time to change the arm which is'in contact with the drum, means to rotate the drum,'and circuit terminals one of which is connected said insulated contacts.

In an instrument of the class described, the combination of a metallic drum having its periphery coveredwith insulating material, a plurality of' rows of metallic c011- 1 10 tacts embedded in said material and in contact with the drum,"-means to rotate said drum, a plurality of contact arms insulated from said drum and mounted to hear thereagainst, a camdevice engaging said arms 115 and permitting but one'oif them to engage said drum at any given time, said arms being adapted to be connected to one terminal of a circuit and said drum to the other terminal, and

and arranged to actuate said cam device intermittently, whereby a different arm is 7 put in contact with the drum.

6'. In an instrument of the kinddescribed,

the-combination o f-a case containing a mo- 1% tor, a 'drumon said case and'connected to be driven by sa-id-motor', said drum having a rim of insulating material, contacts of different lengths embedded in'said material in electrical contact wanna drum and 'ar- 130 to said arms and the otherto lob means carried by the drum 1 20 ranged in a plurality of circumferential rows, the drum being in electrical contact with said case, a bracket mounted on said case and insulated therefrom, a plurality of spring contact arms mounted in said bracket and adapted to bear on the drum, one for each row of contacts, the other terminal of the circuit leading to said bracket, a cam mounted to turn in said bracket and engaging said arms so as to hold all but one of them away from the drum, a star wheel on said cam, and a plurality of adjustable tappet pins carried by the drum and adapted to engage said star wheel to turn said cam. In an instrument of the kind described, the combination with a rotatable drum carrying a plurality of rows of contacts on its periphery, a spring arm adapted to bear on each row of contacts, a rotatable shaft engaging all of said arms and grooved so as to permit but one of the arms to bear on the drum at a time, a star wheel carried by said shaft, pins carried by said drum in position to engage said star wheel, means to hold said pins out of operative position when desired, said contacts being electrically connected to one terminal and said arms to the other, and means to rotate said drum.

8. In'an instrument of the kind described, the combination of a case, a rotatable drum carried thereby, means within said case to rotate said drum, the periphery of the drum being coated with insulating material, a plurality of contacts of different lengths embedded in said material, said contacts being arranged in parallel circles around said drum, a plurality of spring arms, equal in number to the circles of contacts, mounted so as to bear against the periphery of the drum, a cam engaging said arms and constructed to permit one arm only to engage the drum ata time, and removable means carried by the drum and adapted to actuate said cam to permit a different arm to come in contact with the drum.

In testimony whereofi we have hereunto set our hands.

JAMES E. SMITH. CLARENCE W. BURGER.

Witnesses:

S. F. MORRISON, C. A. BRIGHAM. 

